Background: Type B insulin resistance belongs to a class ofdiseases caused by an autoantibody to a cell surface receptor.Blockade of insulin action results in hyperglycemia, hypercatabolism,severe acanthosis nigricans, and hyperandrogenism in women.This rare autoimmune disorder has been treated with variousforms of immunosuppression with mixed success.

Methods: We describe 14 patients with type B insulin resistancereferred to the National Institutes of Health, adding to anexisting cohort of 24 patients. This report focuses on sevenpatients who were treated with an intensive combination protocolof rituximab, cyclophosphamide, and pulse corticosteroids aimedat control of pathogenic autoantibody production. Hematological,metabolic, and endocrine parameters, including fasting glucose,glycated hemoglobin, insulin dose, lipids, and testosterone,were monitored before and after treatment.

Results: All seven treated patients achieved remission, definedas amelioration of hyperglycemia, discontinuation of insulintherapy, and resolution of hyperandrogenism. Glycated hemoglobinhas normalized in all seven treated patients. Remission wasachieved on average in 8 months from initiation of treatment.The medication regimen was well tolerated, with no serious adverseevents.